宽带∑-△A/D转换器中数字抽取滤波器的设计与验证

无线便携式移动设备与宽带intemet接入技术的发展，对∑-△A/D转化器的带宽要求越来越高。文中结合前端5阶宽带乏△调制器，设计了一种降低功耗与面积的数字抽取滤波器，应用于宽带高精度AD转换器中。MATLAB／simulink仿真结果表明，经过数字抽取滤波器滤波后信噪比为97．8dB，通带边界频率为1．8MHz，最小阻带衰减为70dB，通带内波纹0．0025dB，可满足设计要求。∑-△A/D转换器高精度、低功耗的优点，可广泛应用于中特种设备检验检测仪器仪表中。

Design and verification of digital decimation filter for wide-band sigma-delta A/D converter

With the development of wireless portable devices and broadband internet access technology,the bandwidth of sigma-delta AD converter is wider. The purpose of this paper is to design a lower power and less area decimation filter combined with a 5 order of wideband sigma-delta modulator,used for broadband and high precision AD converter.The MATLAB/simulink simulation results after the filtering of decimation filter show that the SNR reached 97.SdB,the passband edge frequency is 1.8Mhz, the minimum stopband attenuation is 70dB and the passband ripple is 0.0025dB,which could meet the design requirements. Sigma-delta AD converter has the advantages of high precision, low power consumption, which can be widely used in special equipment inspection and testing instrument.